Load indicator



June 19, 1923. 1,459,102

H. R. HUGHES LOAD INDI CATOR Filed July 29 1,921

H. R. HUGHES HIS l TTORNEY.

Patented June 19, 1923.

UNITED STATES HOWARD R. HUGHES, OF HOUSTON, TEXAS.

LOAD INDICATOR.

Application led July 29, 1921. Serial No. 488,465.

To all whom it may concern:

Be it known that I, HOWARD R. HUGHES, a citizen ot' the United States,residing at Houston, Harris County, Texas, have invented a certain newand useful Improvement in Load Indicators, of which the following is afull, clear, and exact description, such as will enable others skilledin the art to which it appertains to make and use the same.

My invention relates to load indicators to be used particularly onderricks in well drilling.

The object of my invention is to provide a load indicator which is soarranged as to sustain but a part of the load suspended by the cable andto still furnish an accurate indication of the weight of the load beinghandled.

My invention finds its most important use in indicating the vweight ofdrill stem and drill suspended on the cable from the crown block of thederrick in drilling for oil, water, gas, etc. The weight of the drillstem above the drill in deep wells is sometimes enormous, and it is notonly harmful to the bit to allow this weight to rest completely on thedrill, but the greatest etficiency cannot be obtained in operationswhere the load on the bit is excessive. The

indicator may also be injured or broken by too heavy a load. Bysustaining but a certain fractional part ot the load on the indicator,the dial may be so arranged to show the load with the same accuracy asthough the whole weight rested upon the indicating device.

Referring to the drawin herewith, Fig.

1 shows a side elevation or a drilling rig,

part of the de'rrick being broken away for greater clearness. Fig 2 is aside elevation showing in more detail the crown block on the upper endof the derrick. Fig. 3 is a vertical section through one of the pistonsot the indicator, and. Fig. 4 is a top plan View of the crown block.

This invention is an improvement on the device shown in my prior PatentNo. 1,183,- 646, issued May 16., 1916. The dei-rick indicated at 1 is ofconventional design and is shown as having a platform 2 upon which iscentrally mounted a rotor 3 shown somewhat diagrammatically as grippingthe upper end of the drill stem li. The drill stem is shownais-projecting downwardly into the earth, and has on the lower endthereof, not shown, a drill of any ordinary construction such as is usedin rotary drilling. A mud pump 5 is connected through a pipe and hose 6to a swivel at the upper end of the drill stem for discharging flushingiuid dovlinwardly through the drill stem into the we The drill stem issustained by a traveling block 7 around which the cable 8 is adapted topass. The said cable 8 passes over the different pulleys 9 of the crownblock 10 at the upper end of the derrick. The forward end of the cableextends downwardly at 11 to be wound upon a hoisting drum of ordinaryconstruction, not shown.

The crown block 10 is supported on the cross members 12 at the upper endof the derriclr and usually consists of a plurality ot' pulleys orsheaves supported for rotation by the parallel I-beams 13. I have shownfive of these pulleys in the embodiment disclosed in this drawing. Butone of these pulleys is connected with the indicator. When live of suchpulleys or sheaves are employed l contempla-te mounting the centralpulley 14 upon a separate shaft 15 which is supported at each end inbearings 16 formed on the upper ends of caps 17 of my indica-tingdevice.. The two caps 17 are identical in construction. In Fig. 3 Ihaveshown a vertical section through one of these members. The cap 17 isadapted to fit -closely but slidably over anupstanding cylinder 18 whichis formed with a. closed lower end integral with a supporting plate 19.A laterally extending passage 20 is formed in the supporting plate 19.This passage accommodates a small pipe 21 which is connected fluid-tighttherewith. One ot these pipes 20 is connected with each of the cylinders18, the two pipes21 being themselves connected with the downwardlyextending pipe 22 leading to an indicator 23 oi some well knownconstruction. In the pipe 21 I provide a regulating valve 24 for thepurposeof controlling the flow of duid through 'the said pipe. The cap17 ot the pressure chamber 25 formed within the cylinder 18 is adaptedto maintain a fluid tight tit by means of packing rings 26 formedbetween the contacting surfaces of the cylinder 18 and the cap 17. Ihave also formed in the cap 17 at a point spaced slightly from the upperend of the cap, a laterally extending opening 27. This opening, as willbe noted is, under ordinary circumstances, slightly below the upper edgeof the cylinder 18.

I contemplate using a liquid, such as oil, within the pressure chamber25, the said oil being adapted to fill this chamber and the pipes 21 and22 leading to the indicating dial at 23. Connected with the pipe 22 atits lower end, I have provided a container 28 for a surplus amount ofoil, and in this container I have tted a pump of a hand operated type29. This pump I have connected with the pipe Q2 in such manner that anew supply of oil may be forced into the system when the supply alreadythere has been depleted through leakage or otherwise. When an excess ofoil has been forced into the system by the pump at any time the cap 17will be thereby elevated to such an extent as to allow an escape of thesurplus oil from the opening 27 in the cap 17.

In the operation of this device, onl a portion of the load will restupon the pulley 14 connected with the indicating system. If, forexample, the cable. is threaded over each of the separate pulleys orsheaves of the crown block and downwardly around the sheaves oic thetraveling block 7 in the usual manner, only about one-fifth of the loadwill be sustained by the sheave 14. It will therefore be an easy matterto calculate the proportion of the actual load indicated by the pressureof the fluid against the indicator at incarna 23. rI`he dial may bereadily adjusted to register the exact weight ot the drill stem. rllliiswill avoid the likelihood of breaking o'r injuring the indicator byallowing excessive loads to rest upon the indicating device. A somewhatlighter construction ot' the device will be possible and the liabilityof injury avoided.

Vhile I have shown an indicating device which is Huid operated, I wishit understood that the idea ot sustaining but a small portion of theload upon the indicating device is not confined entirely to fluidoperated indicators, as it isobvious that an indicator consisting ofgears or levers operated from a shaft of the pulley 14 could also beoperated under the same plan.

Having thus described my invention, what I claim as new and desired toprotect by Letters Patent is:

In a load indicator the combination of a derrick, a crown block thereonhaving a plurality of sheaves, a load supporting cable passing over eachof said sheaves. one only of said sheaves being mounted on a shaftsupported by a pressure transmitting means, and a weight indicatorconnected with said transmitting means adjacent the lower end ot saidderrick.

In testimony whereof, I hereunto aliX my signature, this the 16th day ofJuly A. I).

, HUWARD R. HUGHES.

